Electroluminescent display drive circuits (drivers) are traditionally driven by transformers. The transformer driven excitation of the electroluminescent display panel is inherently inefficient due to the capacitive load from the panel being reflected back into the transformer. This causes an efficiency drop due to a power factor loss created by the existence of the inductance of the transformer and the capacitance of the electroluminescent panel.
In addition, electroluminescent display devices have traditionally been driven by high power devices, usually transformers. Although transformers may be necessary to generate high voltage, they are not necessary to drive the electroluminescent displays.
This discovery has far reaching consequences on the art due to the possible reduction of the size and weight of electroluminescent display power supplies. It also has an additional benefit of making the design less susceptible to electromagnetic interference (EMI). Now, the electroluminescent display can be designed to operate at a frequency which will minimize the EMI effects.
Typical of the electroluminescent displays driven by the subject circuitry can be found by referring to U.S. Pat. No. 4,388,554 issued on June 14, 1983, to Suntola et al., which is hereby incorporated by reference.
Another type of electroluminescent display device for dashboards of an automobile is described in U.S. Pat. No. 4,323,895 issued on Apr. 6, 1982, to Coste.
Another electroluminescent display device is described in U.S. Pat. No. 4,320,169 issued on Mar. 16, 1982, to Yatabe et al.
It is an object of the present invention to improve the efficiency of electroluminescent display drivers.
It is a further object of the subject invention to improve the efficiency of electroluminescent display drivers by reducing or eliminating the effects of the power factor created in transformer driven excitation circuits.
It is still a further object of the subject invention to reduce the size and weight of traditional electroluminescent display drive circuits. And it is still another object of the subject invention to eliminate the use of a transformer to drive electroluminescent display panels.